Pop goes the boost pipe

Driving along gently and low revs. Pop! hiss! There goes my boost.

A call to my mechanic and he tells me which ones he's touched doing the cambelt.

Figure out it's below the car and not accessible to me.

Call to the AA and he shows me the tab has sheered itself off!

Fair play to the mechanic who said he'd drive up or pay whatever costs to get it sorted whilst I was over 2 hours away from home. 

Bought the car back with a nice zip-tie bodge and the mechanic is checking it over tomorrow morning to make sure nothing is loose down there and it's all in good working order.